<p>sizer works!</p>
<div>
  <button class="btn btn-success" (click)="dec()" title="smaller">增加</button>
  <button class="btn btn-primary" (click)="inc()" title="bigger">减少</button>
  <label [style.font-size.px]="size">双向数据绑定 FontSize: {{size}}px</label>
</div>
